Sterilization destroys all microorganisms on the surface of an article or in a fluid to prevent disease transmission associated with the use of that item. While the use of inadequately sterilized critical items represents a high risk of transmitting pathogens, documented transmission of pathogens associated with an inadequately sterilized critical item is exceedingly rare.821, 822 This is likely due to the wide margin of safety associated with the sterilization processes used in healthcare facilities. The concept of what constitutes "sterile" is measured as a probability of sterility for each item to be sterilized. This probability is commonly referred to as the sterility assurance level (SAL) of the product and is defined as the probability of a single viable microorganism occurring on a product after sterilization. SAL is normally expressed a 10−n. For example, if the probability of a spore surviving were one in one million, the SAL would be 10−6.823, 824 In short, a SAL is an estimate of lethality of the entire sterilization process and is a conservative calculation. Dual SALs (e.g., 10−3SAL for blood culture tubes, drainage bags; 10−6 SAL for scalpels, implants) have been used in the United States for many years and the choice of a 10−6SAL was strictly arbitrary and not associated with any adverse outcomes (e.g., patient infections).823, Autoclaves are also known as steam sterilizers, and are typically used for healthcare or industrial applications. An autoclave is a machine that uses steam under pressure to kill harmful bacteria, viruses, fungi, and spores on items that are placed inside a pressure vessel., Sterilization destroys all microorganisms on the surface of an article or in a fluid to prevent disease transmission associated with the use of that item..